What is Physics?

WHAT IS SCIENCE? Science is knowledge applied to the Science is knowledge applied to the

natural environment through careful natural environment through careful observation.observation.

Science is trying to explain the Science is trying to explain the world around usworld around us

Science is a way of thinkingScience is a way of thinking Science is a system of knowledge Science is a system of knowledge

based on facts or principlesbased on facts or principles The word science was taken from The word science was taken from

the Latin word “scientia” meaning the Latin word “scientia” meaning “to know”“to know”

A SCIENTIST:A SCIENTIST:Finds answers through

research and experimentation.Confirms results by

repeating experimentsLearns more by

designing and conducting new experiments

Mythbusters use science on every episode…they develop a hypothesis, and then test that hypothesis by performing an experiment

WHAT IS PHYSICS? Physics is the Branch of Science which Physics is the Branch of Science which

studies physical objects (matter) and their studies physical objects (matter) and their behavior (energy) in the universe.behavior (energy) in the universe.

Physics uses mathematical relations to Physics uses mathematical relations to explain and predict natural phenomenon. explain and predict natural phenomenon.

Principles and laws of physics can be Principles and laws of physics can be expressed as mathematical equationsexpressed as mathematical equations..The acceleration of an object depends on The acceleration of an object depends on

its mass and the force applied to it its mass and the force applied to it Newton’s 2Newton’s 2ndnd Law a=F/m Law a=F/m

Physics is considered by many to be Physics is considered by many to be the “central science” the “central science”

EARLY EARLY PHYSICISTSPHYSICISTS

Galileo Galilei Galileo Galilei developed many ideas developed many ideas on mechanics, optics, on mechanics, optics, and wave phenomena and wave phenomena using what is now using what is now known as the known as the Scientific Scientific Method of InquiryMethod of Inquiry..

The Book of nature is written in mathematical characters. ----  Galileo Galilei

EARLY EARLY PHYSICISTSPHYSICISTS

Sir Isaac Sir Isaac described described -universal gravitation -universal gravitation

and the three laws of and the three laws of motion,motion,

-laying the groundwork -laying the groundwork for classical for classical mechanics, mechanics,

-principles of -principles of conservation of conservation of momentum and momentum and angular momentumangular momentum

-He also studied the -He also studied the speed of soundspeed of sound

-and proposed a theory -and proposed a theory of the origin of starsof the origin of stars

ALL SCIENTISTS ALL SCIENTISTS MUST:MUST:

Study problems in an organized manner Make an educated guess as to why things happen Test their ideas through experimentation Collect Data Analyze Results Draw a Conclusion

TESTING A TESTING A HYPOTHESISHYPOTHESIS Experiments often generate more Experiments often generate more

observationsobservations Analyzing data allows us to draw Analyzing data allows us to draw

conclusions about the hypothesisconclusions about the hypothesis The hypothesis can be modified or The hypothesis can be modified or

discarded if it is not supported by discarded if it is not supported by experimental evidence.experimental evidence.

SCIENTIFIC THEORY A reasoned explanation tested by many

observations and experiments Tells why things are, explains how or why

something occurs Three things

Must explain clearly and simply Must be repeatable Must be able to make predictions

Theories can be changed or modified by new evidence

IT’S THE IT’S THE LAWLAWWhen the theory When the theory is used to predict is used to predict new phenomenon new phenomenon then it may, then it may, overtime, become overtime, become what is called a what is called a Scientific Law. Scientific Law. (Describes (Describes Relationships.)Relationships.)

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